The boiling and equilibrium characteristics of subcooled region would be considered as an important advantage in PWRs from the Thermal-Hydraulic point of view. However, the temperature gradient at some sections of reactor core and high temperature of clad surface lead to two-phase condition especially in transient conditions. The high temperature cause the heat transfer regime to change while observing the micro-vapor bubbles in some parts of the fuel channels, and a part of the heat flux changes the liquid phase to steam. This change requires the use of new models to predict fluid/wall temperature and non-equilibrium thermodynamic characteristics. In this research, the simulating of fuel channels during normal and abnormal conditions (PLOFA) was performed by employment of heat transfer models predicting the equilibrium and non-equilibrium characteristics based on the thermohydraulic code developed in Python. The comparison of the results (e.g. flow pattern and temperature profile) and the experimental data shows a good agreement for two-phase flow.
展开▼
